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Cleaning an amp

Discussion in 'Amps and Cabs [BG]' started by Steve S, Jan 27, 2002.


  1. Steve S

    Steve S

    Jul 26, 2000
    I just got a used Peavey amp through ebay and the pots are dirty...all the controls make noise. Can I remove the back and blow air into it to fix it? Or should I take it to a tech?
     
  2. rllefebv

    rllefebv

    Oct 17, 2000
    Newberg, Oregon
    Blowing air through the back will loosen any dust. This is best done with the electronics completely exposed, so that the dust has someplace to go. I'd do this periodically anyway... Dust traps heat, blocks air-flow, etc.

    Pots get dirty and sound staticy, (stat-icky??), and usually air alone will not help. Buy some electrical contact cleaner... can be found at most computer stores, or any Radio Shack. Remove the knobs from the pots and spray this stuff sparingly down the shaft while turning the shaft back and forth. Let it sit for awhile and test... This usually takes care of 75% of the problem. If not, expose the pot, (take the head out of the amp, box, whatever so that you can see the pot)... usually you can see the moving parts of the pot. Spray them sparingly with cleaner also while turning the shaft. That should get it. If you're leery or unsure on any of this kind of stuff, then by all means, take it to a tech.

    Good luck,

    -robert
     
  3. HeavyDuty

    HeavyDuty Supporting Curmudgeon Staff Member Gold Supporting Member

    Jun 26, 2000
    Suburban Chicago, IL
    Don't forget to unplug your amp first!!!

    Bzzzt!
     
  4. rllefebv

    rllefebv

    Oct 17, 2000
    Newberg, Oregon
    :D Whoops!!! I thought that went without saying! Thanks for the cover there Heavy Duty... Your check's in the mail!!

    -robert
     
  5. turn off the amp at the wall, but don't unplug it, because then it is still earthed, this will prevent the static from your hands from damaging any components.
     
  6. My experience with cleaning pots is that you'll be very lucky to clean them effectively by attempting to get cleaning fluid between the shaft and it's bush. You just can't get enough cleaner into the pot like that, especially if it's quite dirty.

    The best way by far is to remove the amp chassis from it's box, then remove any cover plates as nesc to expose the pots. Then you can douse the pots in cleaning fluid, not forgetting to rotate the pots whilst the fluid's in there. Aerosols are best, here. And don't forget to do the job in a place where the fluid won't ruin furnishings, polished surfaces, etc.

    Pots don't always take a clean: they still make a crackling noise after cleaning. Some fluids are better than others: my personal preference is for the "Electrolube" brand but other techies will probably have their own favourite. I also like to use a cleaner that leaves a residue - that's not something usually recomended for pots. Again, it's a personal preference.

    IMHO, there's nothing to worry about regarding static sensitivity. Some of the individual components may well be static sensitive, but the amp as a whole should be OK. Naturally, if you're removing the amp from it's box, then removing cover plates, UNPLUG FROM THE SUPPLY FIRST.

    John
     
  7. Steve S

    Steve S

    Jul 26, 2000
    Thank you for your suggestions. I'll work on it tonite. I've never taken apart an amp before so I hope I don't damage anything.
     
  8. Steve S

    Steve S

    Jul 26, 2000
    I removed the back of the amp. The straw that is supposed to fit into the nozzle of the cleaner was too big so I just sprayed it but couldn't focus the cleaner. The board was completely covered and although I tried to clean it off, still left a lot of residue. Will this hurt the amp? Do I need to take the time to really get around the board and wipe it off completely?
     
  9. HeavyDuty

    HeavyDuty Supporting Curmudgeon Staff Member Gold Supporting Member

    Jun 26, 2000
    Suburban Chicago, IL
    The straw is a really tight fit on purpose - pull the nozzle from the can and try that way. You'll be less likely to get a blast in the face that way, too.

    I would clean up as much of the residue as I could - it's an oil, as I recall.
     
  10. Don't worry too much about the residue on the PCB. It's only electrical cleaning fluid. If you really want to get it off, get something like aerosol Isopropyl Alcohol, sometimes just called IPA. Just hold the amp PCB at an angle then blast it with IPA until all the stuff just washes off. The IPA will probably leave a whitish residue on the PCB when you've done.

    John
     
  11. Steve S

    Steve S

    Jul 26, 2000
    Thank you very much for your help. I've appreciated the people on this site who have provided much needed guidance to me.

    Thanks again!